Genetics, Gender and Mortality: How Gender Affects the Aging Process

Researchers have recently concluded that in humans, mortality rates are higher for males than females. This conclusion brings with it a host of important questions about genetics, gender, and health habits. There are many factors that come into play when determining mortality rates, such as engagement in high-risk behaviors, diet and exercise habits, and stress levels. Many researchers believe, however, that our genetic makeup and gender determine how we age more than any other factor.

For decades, medical scientists have examined the mathematical relationship between age and mortality, or the "law of mortality," which has become pivotal to the studies of senescence. Senescence, or cellular deterioration, is a natural part of the aging process, and affects how we age on every level. Senescence causes the decrease of function of all cells, organs and tissues as a human b ages. These changes directly lead to the outward signs of aging. Senescence is a natural occurrence in the human body, and not considered a disease, though it can make the body more susceptible to diseases, particularly as the immune system breaks down.

Evidence of Gender Differences in Aging

There are many genetically determined physiological differences between men and women that affect the aging process. For instance, men have naturally high levels of testosterone. Researchers have found that testosterone is detrimental to the immune system, thereby decreasing men's abilities to fight disease. Scientific studies have shown that when testosterone is removed from the male body, the number of immune cells available to fight disease increases. These physiological differences are important, but they are not the only determinants when it comes to aging differences between our two genders.

When considering the mortality rates between males and females, differences between the nature of men and women are also important. Studies have shown that in general, women tend to be much more sensitive and attentive to their bodies than their male counterparts. Research has concluded that males tend to engage in high-risk activities more frequently than females, and often have higher stress levels, both factors that affect mortality rates. While genetics do play a part in the aging process, they're not the only thing that determines how quickly we age; other factors include:

• alcohol consumption
• cigarette smoking and drug use
• diet
• exercise habits
• exposure to pollutants
• stress levels.

Theory and Findings on Female Aging

Researchers have found that human females, who experience shorter life spans than males, typically senescence at earlier ages than males; this means that their cells begin to deteriorate faster and sooner than the cells of men. Following are some findings that deal with gender difference, senescence and life span.

• One approach states that women who have children in their earlier years will experience cell deterioration even earlier than those who reproduce at a later age. Studies have proven that women whose last reproduction was at an older age lived longer and therefore senesced at a slower rate than those who reproduced earlier in life.

• Secondly, "the grand mothering hypothesis" states that mothers begin to senesce (and begin menopause) earlier than women without children in order to care for their children and help them to reproduce themselves. Senescence of fertility is thought to be nature's way of canceling "reproductive competition" between mother and daughter.

• Lastly, although women have been shown to senesce quicker than men, women who begin menopause at a later age will have a longer life span. During menopause, a woman's level of estrogen decreases dramatically. Estrogen has been proven to have positive effects on the body. Therefore, the longer a woman's body is exposed to estrogen, the better condition it will be in.

Aging, Gender Differences and You: The Power is Yours

Aging is a difficult process both emotionally and physically, not only for the elderly, but also for their friends and family. It is important to remember that aging is a part of life, and is important to honor one's body. Regardless of a person's gender or cellular makeup, there are many practices that are helpful in staying healthy and working towards increasing lifespan. It is important to practice healthy living throughout your life. While there's no sure way to increase your lifespan, doctors recommend taking such steps as maintaining a balanced diet, keeping stress levels low and following a regular exercise program. It is possible that a person's gender and genetic makeup make a person more susceptible to certain tendencies in terms of disease and aging, but the ultimate way of life is up to him or her.

Resources

Blarer A., Doebeli M., Stearns S.C.Diagnosing senescence: Inferring evolutionary causes from phenotypic patterns can be misleading. (Dec. 1995); Proceedings of the Royal Society B: Biological Sciences. Volume 262 (1365): 305-12.

Dent, E. Testosterone emasculates the male immune system. (Dec. 2004); National Review of Medicine, 1(23).

Graves B.M., Strand M., Lindsay A.R. A Reassessment of sexual dimorphism in human senescence: Theory, evidence, and causation. (Mar. 2006); Am J Hum Biol., 18(2): 161-8.

Helle, S., Lummaa, V., Jokela, J. Are reproductive and somatic senescence coupled in humans? Late, but not early, reproduction correlated with longevity in historical Sami women. (Jan. 2005); Proceedings of the Royal Society B: Biological Sciences. Volume 272 (1558): 29-37.

Legendary Pharmaceuticals. Background: Introduction to the biology of aging and senescence. Retrieved June 30, 2009, from the Legendary Pharmaceuticals Web site: http://www.legendarypharma.com/.

Maul, G. Grandmother hypothesis of menopause. Retrieved July 1, 2009, from the Medical News Today Web site: http://www.medicalnewstoday.com/articles/102347.php.

Mirkin, G. (2005). Longevity associated with late menopause. Retrieved July 1, 2009, from Dr. Mirkin's Web page: http://www.drmirkin.com/women/2224.html.

Newswise Science News. (2009). Gender differences in aging reassessed. Retrieved June 30, 2009, from the Newswise Web site: http://www.newswise.com/articles/view/521028/?sc=swtn.

Strategic Practices. (2009). Gender, care and agency. Retrieved June 30, 2009, from the Strategic Practices Web site: http://research.jyu.fi/strategicpractices/Gender